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Voltage Drops - Really Struggling!

  1. Apr 1, 2016 #1
    • Thread moved from the technical forums, so no HH Template is shown.
    Hi all

    Wondering if anyone can help. Really dont know where to start

    I know Zs = Ze + Z1 + Z2

    and Z1 = PCR 8.9 milli-ohms/meter
    and Z2 = CPC 14.5 milli-ohms/meter
    which equates to 0.0234X milli-ohms/meter over X meters

    but where does my volt drop come in if I dont know my current?

    Regards 9.PNG
     
  2. jcsd
  3. Apr 1, 2016 #2

    CWatters

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    If the fuse is 32A the current could be any value <32A ??
     
  4. Apr 1, 2016 #3
    1. The problem statement, all variables and given/known data
    230 V, 50 Hz supply (TN)
    Ze = 0.8 ohms
    Z1 = 8.9 milli-ohms/meter
    Z2 = 14.5 milli-ohms/meter
    Volt-drop/Amp/meter = 18 mV/A/m
    2. Relevant equations
    Zs = Ze + Z1 + Z2
    V / Zs = I ??????

    3. The attempt at a solution
    Zs = Ze + Z1 + Z2
    Zs = 0.8 + (0.0089 + 0.0145)X..........................where X is the distance in meters
    Zs = 0.8 + 0.0234X

    Then
    230V / (0.8 + 0.0234X) = I

    Not sure if this is correct!
    Also is this relevant:
    TN system.... I know that for final circuits up to 32A disconnection time should not exceed 0.4secs
    Voltage Drop, lighting circuits = 3%max and other circuits 5% max
    if this is correct then 230V * 0.05 = 11.5V

    Not sure if this is right approach

    Any help?

    Cheers
    9.PNG
     
  5. Apr 2, 2016 #4
    Anyone????
     
  6. Apr 2, 2016 #5

    CWatters

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